1. Field of the Invention
The present invention relates to a map information display system for a moving body for extracting map information from a storage medium and displaying the map information.
2. Description of Related Art
A device such as that disclosed in Japanese Patent laid-open No. Hei. 7-83684 is known as a map information display device for extracting and displaying map information of a specified region. This device extracts map information in such a way that the size of the map information becomes smaller than the storage capacity of a memory when the size of map information set to be extracted by an operator of the map information display device is larger than the storage capacity of the memory in the device. The device extracts the map information by selecting a map from which part of a route selected by the operator is deleted or a map having a reduced scale, and stores the information into the memory.
However, since the above-described device of the related art removes part of a route set by the operator, the route or way points are updated. This causes a problem in that updating movement schedules or plans for a trip or a bike tour etc. is unavoidable. Furthermore, when the capacity of map information is reduced by selecting a reduced scale map, it will sometimes be the case that required map information is not included in the reduced scale map information. This causes a problem in that desired map information cannot be extracted.
The present invention has been conceived in view of the above mentioned problems, and an object of the invention is to provide a map information display system for a moving body that can extract and display desired map information without updating way points or routes set by an operator.
A map information display system for a moving body according to the present invention comprises coordinate information generating means for generating route point coordinate information representing points on a route being traveled by the moving body and on a scheduled route; limited region map information generating means for extracting map information for only a limited region based on the route point coordinate information from map information stored in a storage medium and including road information, and generating limited region map information; storage means for storing the limited region map information; and display means for displaying the stored limited region map information. The limited region map information generating means comprises route generating means for generating a moving body route based on the route point coordinate information and the road information; extracting means for setting map information of a strip-shaped region extending along the moving body route as the limited region map information; and strip-shaped region adjusting means for adjusting a size of the strip-shaped region so as to include the moving body route when it is determined that the information amount of the limited region map information is larger than a specified storage capacity less than a storage capacity of the storage means.
Specifically, according to one aspect of the present invention, when it is determined that the size of the limited region map information is larger than the storage capacity of the storage means, the size of the strip-shaped region is adjusted so as to include the moving body route. This means that it is possible to extract and display required map information without updating the route and way points set by the operator.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.